Embodiments of the present disclosure relate to wind turbines, and more particularly to methods and systems for optimizing one or more wind farm metrics.
A wind turbine converts wind energy into electrical energy. For this conversion, the turbine includes one or more rotor blades that convert wind energy into mechanical energy as wind blows across the surface of the blades, and a generator (coupled to the rotor blades) that converts the mechanical energy of the rotating blades into electricity. Other components such as a step-up gearbox to increase rotation speed, blade control mechanism to alter rotor efficiency and turbine loads (for example: full-blade pitch actuators), a yaw mechanism to track the wind direction, aerodynamic and mechanical braking mechanisms to stop the turbine, and a cooling unit to cool the gearbox and the generator during operation may also be present.
A single wind turbine may generate enough electricity to supply power for a house or a farm. However, the single wind turbine may not be able to generate enough electricity to supply power to an entire town. Therefore, for large grids, a wind farm (collection of turbines) may be implemented. The turbine outputs may be connected to a common output, which powers nearby areas.
Typically, in a wind farm, each wind turbine attempts to maximize its own power output while maintaining its fatigue loads within desirable limits. To this end, each turbine includes a control module, which attempts to maximize power output of the turbine in the face of varying wind and grid conditions, while satisfying constraints like sub-system ratings and component loads. Based on the determined maximum power output, the control module controls the operation of various turbine components, such as the generator/power converter, the pitch system, the brakes, and the yaw mechanism to reach the maximum power efficiency.
Often, while maximizing the power output of a single wind turbine, neighboring turbines may be negatively impacted. For example, downwind turbines may experience large wake effects caused by an upwind turbine. Wake effects include reduction in wind speed and increased wind turbulence downwind from a wind turbine typically caused by the conventional operation of upwind turbines (for maximum power output). Because of these wake effects, downwind turbines receive wind at a lower speed, drastically affecting their power output (as power output is proportional to wind speed). Moreover, the turbulence effects negatively affect the fatigue loads placed on the downwind turbines, and thereby affect their life (as life is proportional to fatigue loads). Consequently, maximum efficiency of a few wind turbines may lead to sub-optimal power output, performance, or longevity of other wind turbines in the wind farm.
Certain currently available techniques attempt to optimize the wind farm power output rather than the power outputs of individual wind turbines, through coordinated control of the wind farm turbines. These optimization techniques, however, optimize a single turbine control parameter, such as an angle of inclination of rotor blades (or a blade pitch angle). Optimization of these physical parameters may not affect turbine behavior over its entire operating range, and might inadvertently alter other parameters and therefore prevent effective maximization of the achievable power output from the wind farm. Moreover, these techniques merely attempt to maximize only the power output of the farm and fail to optimize any other farm related metric, such as fatigue loads, or turbine component life.